A portable device is known that has a first housing, and a second housing connected to the first housing so as to be able to be superimposed on the first housing (Japanese Laid-open Patent Publication No. 2002-232220, Japanese Registered Utility Model No. 3027116, and Japanese Laid-open Patent Publication No. 2000-17466). Some of the portable devices include an antenna in the second housing. In these portable devices, the wall portion of the second housing surrounding the antenna is formed of insulating material in order to suppress influence on the transmitting and receiving of radio waves by the antenna.
In the superimposed state, the antenna housed in the second housing faces the first housing with the wall portion of the second housing therebetween. Therefore, depending on the material of the first housing, the first housing may exert influence on the receiving sensitivity of the antenna in the superimposed state.